No wounded left behind — not quite. Ants that have evolved battlefield medevac carry only the moderately wounded home to the nest. There, those lucky injured fighters get fast and effective wound care.

Insect colonies seething with workers may seem unlikely to stage elaborate rescues of individual fighters. Yet for Matabele ants (Megaponera analis) in sub-Saharan Africa — with a mere 1,000 to 2,000 nest mates — treating the wounded can be worth it, says behavioral ecologist Erik Frank at the University of Lausanne in Switzerland.